SmartWool's everyday boot sock has just enough cushioning to keep your feet comfy throughout the day. Merino wool, nylon, elastane. Medium cushion under the foot for extra comfort. SmartWool delivers soft, itch-free comfort, even foot temperature, moisture management, and odor control. WOW (wool on wool) Technology adds more wool in high-impact and high-wear areas to reduce shock and abrasiona "offers more comfort and longer lasting merino wool benefits. Knee-high height. Machine wash warm inside out, gentle cycle; tumble dry low or line dry.